Patent Document 1 below contains a description of a conventional inductance element circuit constant analysis method. The equivalent circuit of the inductance element in this Patent Document 1, as shown in FIG. 1(B), is configured as a parallel circuit including an inductance Ls, a capacitance Cp, and a resistance Rp. To this parallel circuit, added are:
(a) another capacitance Cr connected in series to the above-described resistance Rp,
(b) another inductance Lr connected in parallel to the above-described resistance Rp,
(c) another resistance Rs connected in series to the above-described parallel circuit,
(d) a first closed circuit including a resistance Rm1 and an inductance Lm1 so as to be magnetically coupled with the above-described inductance Ls with a coupling coefficient k1 by way of a mutual inductance M1, and
(e) a second closed circuit including a resistance Rm2 and an inductance Lm2 so as to be magnetically coupled with the above-described inductance Ls with a coupling coefficient k2 by way of a mutual inductance M2. Furthermore, M1=k1·√(Ls·Lm1) and M2=k2·√(Ls·Lm2).
By the use of this type of equivalent circuit, circuit constant analysis can be performed at high accuracy that is capable of good indication of the characteristics of an inductance element, and it is particularly possible to perform circuit constant analysis that is useful for an inductance element utilizing a ferrite material.
However, when the above-described background art equivalent circuit is used for approximation of an inductance element having characteristics as indicated by the solid line curve in FIG. 2(A), the resultant characteristics become similar to those shown in FIG. 2(C). Upon comparison of both of these curves, a good result is found to have been obtained overall for the inductance L and also the Q value. In particular, sufficiently approximated characteristics are obtained in the band region less than or equal to the resonance frequency (L>0).
Furthermore, a specific example of the circuit constants for obtaining the characteristics of FIG. 2(C) is listed as follows for the parallel circuit constants of Ls=4.8 μH, Rp=4100Ω, and Cp=1.3 pF:
(a) Lr=33 μH,
(b) Cr=0.86 pF,
(c) Rs=0.46 Ω,
(d) Lm1=4.8 μH, Rm1=27.1Ω, k1=0.22,
(e) Lm2=4.8 μH, Rm2=307.5Ω, k2=0.133.
However, in the band region greater than or equal to the resonance frequency, the Q value is excessively high, and the approximation of loss is not necessarily sufficient. Although, for example, the noise countermeasure function of an impedance element is realized at frequencies greater than or equal to the resonance frequency, if the above-described conventional equivalent circuit is used, then a good simulation for verification of this function might not be possible in the high frequency region at frequencies greater than or equal to the resonance frequency.